1. Field of the Invention
The present invention relates to an apparatus for creating a turning program used by a lathe or other machine tool.
2. Description of the Related Art
There are known numerical controllers or automatic programming apparatuses that automatically create a machining program from input information such as the shape of the material to be turned and the machined shape (final shape). When a machining program is automatically created in such a way, the material shape and machined shape are interactively defined and input by arcs and straight lines, as instructed by on-screen guidance, and the tool and machining conditions are selected and determined automatically.
When a machining program for finish turning (including semifinish turning) is automatically created in an interactive manner, the cutting direction is generally set to follow the profile of the machined shape.
However, depending on the shape of the cutting tool, the cutting performance and finish accuracy may vary with the cutting direction or chips may need to be disposed of properly, so in some situations, cutting may proceed from the rim toward the center of the workpiece instead of following the machined profile.
For example, Japanese Patent Application Laid-Open NO. 2-145237 discloses a contour shape machining method, which specifies the cutting direction for each element of the machined shape to suit the tool shape.
To select and set the optimum cutting direction for finish machining (including semi-finish machining), the cutting direction needs to be set for each element of the machined shape, as described in the above patent document. Therefore, it is difficult for a non-skilled operator to select and set the optimum cutting direction, taking the cutting efficiency and accuracy into account. In addition, creating a machining program by setting the cutting direction for each machining element is time-consuming and troublesome.